Levels of lysosomal enzymes in tissues of mice infected with Mycoplasma fermentans

Abstract

The effects of a toxic dose of Mycoplasma fermentans on levels of lysosomal enzymes in mice were examined. Washed cell suspensions (approximately 1010 colony-forming units) of a recent isolate of M. fermentans were injected intraperitoneally into 3to 4-week-old BALB mice, and levels of acid phosphatase and beta-glucuronidase were monitored in liver, spleen, thymus, and serum. Levels of acid phosphatase remained essentially normal, but levels of betaglucuronidase were markedly elevated in serum and to a lesser extent in liver and thymus. The peak response of serum beta-glucuronidase was noted at 8 h postinjection, with a level of 30 gg of phenolphthalein released per ml per h, representing a six-fold increase over control levels. Pretreatment with BCG did not potentiate the effect as it did with endotoxin. The implication of this increased lysosomal enzyme activity in "lethal toxicity" is that that the increase may be secondary to some other cytotoxic event, or that the affinity of mycoplasmas for biological membranes may be involved. The data suggest that the role of lysosomal enzymes in other models of mycoplasma-induced disease should be evaluated.

The mycoplasmas.

“…Killed mycoplasma cells or fractions thereof can also be toxic to animals (94). Injection of large quantities of killed M. fermentans cells or membranes killed mice with symptoms resembling those of gram-negative endotoxemia, including thymic involution and an increase in the level of the lysosomal ,B-glucuronidase in the serum (94,97,99,100). These data could suggest that mycoplasmas possess an endotoxin resembling that of the gram-negative bacteria, as was proposed earlier by Villemot et al (337).…”

“…Our present knowledge of the mycoplasma membrane composition, however, rules out the presence of any molecules resembling the classical bacterial lipopolysaccharides (see Membrane Lipids). Hence, it is not surprising that the toxemia due to M. fermentans cells or membranes differed in some important details from that caused by lipopolysaccharides (99,100), and the Limulus amoebocyte lysate coagulation test, capable of detecting extremely low doses of lipopolysaccharide, remained negative in mice injected with M. fermentans (92). Thus, the nature of the toxic factors in M. fermentans cells and membranes is still unclear (see also Organ Cultures as Experimental Systems).…”